Fertilizer response of barley grain in south and central Alberta

Abstract

The rate of N fertilizer application is among the most critical decisions for barley (Hordeum vulgare L.) grain production because of its large impact on grain yield, protein content and input cost. A field study was conducted to determine the optimum rate of N fertilizer for a range of barley cultivars in south and central Alberta. Experiments were conducted at 20 sites over 3 yr (1997 to 1999). Nitrogen fertilizer was applied at 0, 40, 80, 120, and 160 kg N ha-1 to 10 cultivars. Grain yields were highest for the two semi-dwarf cultivars (CDC Earl and Kasota) and three of the five general-purpose cultivars (AC Harper, AC Lacombe, Leduc) (high-yielding cultivars) and least for the hulless cultivars (Falcon and Phoenix). Grain yields of the two remaining general-purpose cultivars (CDC Fleet and Seebe) and the malt cultivar (Harrington) were intermediate (medium-yielding cultivars). The economic optimum rate of N fertilizer (NFopt) for high-yielding cultivars was 14 kg N ha-1 higher than for medium-yielding cultivars and 24 kg N ha-1 higher than for hulless cultivars. Maximum grain yields for all cultivars were obtained when the ratio of available N (fertilizer + soil-derived N) to maximum grain yield exceeded ~28 kg N Mg-1. Soil-derived N was highly correlated with both pre-seeding soil NO3-N and growing season precipitation. Protein concentrations were highest for hulless cultivars and least for high-yielding cultivars, and increased linearly with increasing N availability. Barley responses to P, K, S and micronutrients were also tested in this study and showed similar responses to earlier studies. The optimum rate of N fertilizer for barley in this study was obtained when the ratio of available N (fertilizer + soil-derived N) to maximum grain yield was 25 to 30 kg N Mg-1. Key words: Hordeum vulgare, nitrogen fertilizer use efficiency, malting barley, protein